Building the Dumbo

Part 2 of 3

Published in

Make School

6 min readOct 14, 2015

Greetings all and thanks for coming back!

I have been hard at work building my quad copter, Dumbo, and would like to share with you the first piece of my journey.

Building a quad copter not only takes a bit of knowledge and perseverance, but also a few different tools! For this build, I needed a soldering station, power drill, and some miscellaneous stuff like hex wrenches and screw drivers. (I managed to pick up a few other goodies in the process as well.)

After purchasing the necessary tools, I was anxious to get building! I received a large brown box in the mail and even before opening it I knew that it contained what I had been waiting for: Dumbo’s parts.

I had plans to go to the beach that night, but I had to start building and decided to cancel the beach trip in favor of making a flying robot — a good choice if you ask me. So I went to my room, sat down, placed the box on my lap, cut through the tape, and was greeted with a myriad of electromechanical doodads.

The first thing I pulled from the box was the transmitter (aka radio, aka remote control).

I picked it up and…there was something rattling around inside of it, like an internal piece had broken off. So naturally, I investigated. And by investigated I mean I took the damn thing apart so that I could extract whatever was banging around in there. (A questionable idea as the transmitter was brand new and still under the factory warranty, which would surely become void if I started taking the transmitter apart.)

The good news: I was able to successfully find and remove what was rattling around inside the transmitter.

The bad news: I have no idea what that screw came off of and am probably going to regret voiding that warranty sometime soon when my transmitter stops workings.

After solving the mystery of the rattling transmitter, the next thing I pulled out of the box was the frame. (Well really, it was a small box of parts that could be assembled into a frame.)

After about an hour of tinkering I managed to get this:

If you’re wondering why that yellow ball is attached to the frame, it’s to decrease the pilot’s chances of crashing. No, it doesn’t effect the aerodynamics in any noticeable way or provide cushioning on impact, but it does at least indicate the front of the vehicle…which is pretty important to know when flying, if you didn’t know.

The next thing I pulled out of the box were these — the motors.

I was confused on how these things were supposed to be mounted onto the frame, but with a little trial and error I managed to figure it out.

I was pretty excited at this point as Dumbo was actually starting to look like a quad copter.

The next objects I pulled from the magical box of parts were the electronic speed controllers (aka ESCs).

Up until this point, you could probably guess the utility of the objects pulled from the box, but ESCs aren’t as well known so let me give you a little background information:

They control the motors.

Great, now that you know all about ESCs let’s move on.

If you look closely, you will see that neither end of the ESCs have any connectors, that is, both sides are just wire. To connect the ESCs to the motor I needed to solder onto the blue wires what are known as bullet connectors.

Luckily, when ordering parts, I had the foresight of ordering 10 3.5mm bullet connectors and 10 4.0mm bullet connectors for cases specifically like this one, so that I wouldn’t get bogged down by these small issues.

…But wait, I needed to solder 3 3.5mm bullet connectors onto each ESC, meaning I needed 12 3.5mm bullet connectors in total, but I only had 10.

First, I checked Amazon. They had what I needed, but couldn’t delivery it for two days, and there was no way that I was going to put the build on hold for two days. So I went to Orchard Supply Hardware. When I asked them where their bullet connectors were located, they looked at me like I was crazy; they had no knowledge of bullet connector, and had never even heard the name before. So I tried Home Depot, surely they would have bullet connectors…Nope. They too had no clue about what I was talking about. So then I called PepBoys, who Google suggested, and luckily they knew about bullet connectors and had them in stock!

…But the smallest size they carried was 4.0mm, and I needed 3.5mm.

At this point, I had wasted about 4 hours and $40 on Uber rides trying to find these damn 3.5mm bullet connectors. I started getting desperate and became more creative with my Google searches; I found a small model shop in Santa Monica: Evett’s. Although priced at $1.50 a connector (Amazon had them priced at $0.25), Evett’s Model Shop had the 3.5mm bullet connectors that I needed to continue my build!

And finally, with the necessary parts in hand, I was able to solder the bullet connectors onto my ESCs.

That wooden block near the top of the picture was used as a bullet connector holder— a very useful hack for anyone needing to solder anything onto bullet connectors.

Now that I had the frame, motors, and ESCs ready to go, the next step was connecting the motors to the ESCs.

And the next step after that was getting the leads of the ESCs soldered to what is known as a power distribution board. Since each ESC needs power, we solder the positive leads of each ESC to one electrically connected track on the power distribution board and all the negative leads to the other track. We then connect the battery directly to the power distribution board such that it powers the positive and negative tracks, thus powering all ESCs from one battery.

The green board in the center of the frame is the power distribution board.

After getting everything soldered together (and surviving the bullet connector fiasco), the hard part was over.

Now all I had to do was install the flight controller and receiver. The flight controller is the brains of the operation; it consists of an accelerometer, gyroscope, magnetometer, and a small computer chip. The receiver communicates with the transmitter and sends instructions to the flight controller. The flight controller takes input from the receiver and reads the values from its sensors (the accelerometer, gyroscope, and magnetometer) to determine how fast to spin each motor. (Quad copters move by changing the speed of each motor, which changes the thrust produced by each propeller, which applies a force to the vehicle, which causes movement.)